Trip-time-based Congestion Detection

To regulate network traffic and ensure that every user can get a reasonable quality of service whatever the load, networking protocols need to implement some sort of congestion control. To be able to control congestion, one must first know when it occurs and to which extent. This is the scope of congestion detection. Till now, congestion detection has only been based on packet losses. Protocols like TCP assume that a packet loss is a consequence and a signal of the network’s overload. Anyway, this detection scheme has a number of flaws1. In this report, we discuss the possibility of detecting congestion from the packets’ trip times. We first analyse the characteristics and distribution of One-way Trip Time or OTT. We then design a scheme of detection based on OTT measurements, and validate this scheme by simulation over a large range of situations. 1 Distribution of the One-way Trip Time